How to Handle Post-Harvest Leftovers

The main goal of most growers is to harvest unfertilized flowers full of active compounds and terpenes. But what about the "leftovers" — the trim, leaves, stems and roots? For many growers these are mere waste that ends up in the bin or compost, but that is a real shame. These parts of the plants contain valuable compounds that can be turned into homemade medicine, cosmetics or treats.

Harvest time is always a moment of joy for growers, but it also brings extra work. Remember that if you decide to use the leaves or roots further, you should treat them during harvest and drying with the same care as the flowers. During drying pay attention to the correct conditions: low relative humidity around 55%, temperature between 18–21 °C, darkness and fresh air supply. Under no circumstances use moldy dried material or plants treated with pesticides for further processing.

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Sugar leaves

The English term "sugar leaves" refers to the small leaves around the flowers that are covered in trichomes and contain a relatively high amount of cannabinoids and terpenes. You can make effective extracts, tinctures or balms from them, or use them similarly to flowers (rubbing off resin, vaporizing herbal blends).

Remember that CBD in dried material appears in its acidic form (CBDA), which is inactive when ingested. For CBDA to convert to CBD, the dried material must first be decarboxylated, i.e. heated to a sufficiently high temperature for a certain time. Decarboxylation occurs to some extent during the actual cooking of oil or balm, but for better effects of the final product it is preferable to heat-treat the dried material first.

• Infused butter or oil: Cannabinoids bind very well to fats, so cooking dried material in butter, oil or another fatty carrier (coconut oil, lard) is a very effective extraction method. Simply gently heat an appropriate amount of dried material at about 80 °C for 2–3 hours and then strain.
• Homemade herbal salve: There is ample evidence that CBD and other cannabinoids are very effective with topical application, especially for pain, eczema and skin injuries. As a base for a homemade salve you can use medical petroleum jelly, coconut or olive oil, shea butter or lanolin. The basic preparation is simple: add approximately 20–50 grams of dried material to one kilogram of carrier and heat the mixture in a water bath or in an oven set to a low temperature for about 2 hours. The mixture temperature should not exceed 80 °C to avoid degrading the cannabinoids. You can then strain the mixture or let it cool and repeat the heating process several times to extract the maximum from the dried material.
• Tincture: Like fats, alcohol is also an excellent tool for extracting active compounds from herbs. The "Green Dragon" — a high-alcohol herbal tincture — was historically used for pain or insomnia. Preparation is simple: add about 10 grams of decarboxylated dried material to 200 ml of strong alcohol and seal in a bottle or jar. Let the herbal-alcohol mixture macerate for several weeks at room temperature in a dark place. Finally, filter the mixture through a coffee filter.
• Collecting resin: As with flowers, the leaves around them contain a significant number of stalked and capitated trichomes that hold active compounds and terpenes. Trichomes can be separated from the rest of the dried material mechanically or with a suitable solvent. The result is a concentrated "resin" (hash, ice hash, rosin, resin) with a high share of active compounds and terpenes. Collecting resin through a fine sieve (so-called dry sift) is one of the oldest methods for producing herbal concentrates.
• Vaporization: Inhaling vapors rich in active compounds and terpenes is a very effective and fast way to consume medicinal herbs. The most suitable material for this is thoroughly cleaned, dried and well-matured flowers without seeds, but the leaves around the flowers also hold medicinal potential. However, consumers should be prepared for them to be less delicate in taste. A great way to add a pleasant aroma to less aromatic dried material are terpene sachets.

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Large leaves

Trichomes on large leaves contain much smaller amounts of cannabinoids and valuable monoterpenes compared to those on flowers. However, they are rich in antioxidants, chlorophyll, fiber, minerals and vitamins, which makes them a great ingredient for the kitchen. You can also process them into salves, but expect to need a larger amount of dried material than you would if you used flowers or sugar leaves.

• Green smoothie: Add fresh leaves to your favorite smoothie.
• Herbal tea: Pour hot water over dried leaves and let steep. The infusion will have an earthy taste and calming effects. You can add other herbs to the tea, such as mint, lemon balm or ginger and honey.
• Salads: You can use the leaves in salads. They have a pronounced flavor that pairs well with mustard dressing, strong cheeses and fruit.

Roots

Roots are perhaps the most overlooked parts of the plants by growers, yet they have a long tradition in folk medicine going back thousands of years. Ancient Chinese, Greek and Roman texts describe decoctions, poultices and pastes from roots used for pain, inflammation, cramps or bleeding. Even in the 18th and 19th centuries they were recommended for rheumatism, inflammations or urinary problems. Roots contain only trace amounts of cannabinoids, mainly CBD, but they also contain friedelin and epifriedelanol, compounds known for antioxidant, anti-inflammatory and antitumor effects.

• Tincture: Roots are a great ingredient for the "Green Dragon" tincture described above.
• Balm or salve: You can also add roots to an herbal salve. First dry them and then crush into pieces or a fine powder. Then add the roots to the herbal salve and proceed according to the instructions above.

Stems

Stems contain the least active compounds of all the plant leftovers, but they are rich in cellulose and lignin, i.e. strong plant fibers. The best uses are composting or mulching, or you can make decorations from them. We do not recommend using dried stems as plant supports, because they can become moldy and spread mold spores to the surroundings.

For more tips and guides for beginner growers and experienced growers, visit the Higarden blog.